Only dexoxadrol, not its enantiomer, levoxadrol, nor the diastereomeric racemate, Beta-dl-dioxadrol, had good affinity for the phencyclidine receptor and was active in drug descrimination assays in pigeons and monkeys trained to ketamine. Since our X-ray crystallographic structure determination has shown us the absolute 3-dimensional structure of dexoxadrol, we can now relate a minimum energy conformation needed for interaction with the phencyclidine receptor and have definitive evidence for the receptor's stereospecificity.